1. Field of the Invention
The present invention relates to meshing gear transmissions for transmitting and varying torque and speed from input torque and speed. More specifically, the invention sets forth a compact, constant mesh gear arrangement using uncomplicated shaft forms enabling many different ratios to be realized from a minimal number of gears and shafts. The invention finds utility in the automotive field, broadly defined. The invention is usable in powered motor vehicles wherein wheels, propellers, propulsion screws, and the like must be operated at speeds and torques varying from those of a power plant. Motor vehicles, including automobiles, trucks, and motorcycles are the principal but not sole applications. Of course, machine tools and machinery generally requiring gear reductions may utilize the present invention.
2. Description of the Prior Art
Motor vehicles relying on internal combustion engines having a rotating power output shaft have long had to match power and rotational speed of the engine to actual requirements. In most cases, the engines are high speed, and require reduction in shaft speed from the engine to the driven element, such as powered road wheels. Since power demand for different aspects of vehicle operation varies considerably with conditions, more than one reduction ratio is required. General purpose road going automobiles are currently available with four, five, or six forward speeds. Road going, freight hauling trucks may have sixteen speeds. The greater the number of available reduction ratios, the greater the versatility of the drive train with respect to fuel efficiency, engine life, acceleration, noise, and similar aspects of operation.
Conventional transmissions employ plural spur or helical cut gears. The gears ride on supporting shafts, and are keyed by splines or interface with dogs formed on splined engagement rings or gears to their shafts. The engagement rings are slid along the shaft, turning in lockstep therewith, and mesh with dogs formed on the face of each gear. Gears are provided in meshing pairs, each one of the pair supported on one shaft. The number of gears required to provide a predetermined number of reduction ratios usually exceeds the number of available ratios. Examples are seen in U.S. Pat. No. 971,883, issued to Kenneth W. Gant on Oct. 4, 1910, U.S. Pat. No. 1,064,365, issued to George D. Munsing on Jun. 10, 1913, U.S. Pat. No. 1,277,251, issued to Johann Klaus Ott on Aug. 27, 1918, U.S. Pat. No. 1,362,490, issued to Robert Keck on Dec. 14, 1920, and U.S. Pat. No. 1,415,515, issued to Constant Bouillon on May 9, 1922. In most of these examples, the subject transmission employs conventional elements such as three shafts, these being an input shaft, an output shaft, and a counter shaft, shift forks, and toothed gears which rotate on the three shafts.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.